1. Field of the Invention
The present invention is directed, in general, to a metering mixing faucet and, more particularly, to a metering mixing faucet that allows for adjustment in the temperature of the fluid dispensed by the faucet.
2. Description of Related Art
Many faucets include metering valves to limit the amount of water discharged by the faucet in each operating cycle in order to minimize waste of water. Such faucets are particularly useful in commercial installations. Most metering faucet assemblies currently in use include valves that are designed to be manually operated open and, after release of the operating handle, to close after a metered amount of water has been discharged. Additionally, automatic metering faucet assemblies have been introduced which are operated in response to detection of a user's hands coming into the proximity of the faucet assembly.
In most known metering faucet installations, the relative proportions of hot and cold water in the mix are factory preset. Metering faucet assemblies have been proposed that allow adjustment in the amounts of hot and cold water in the mix, and thus the temperature of the water being discharged by the metering faucet. For example, U.S. Pat. No. 4,457,452 to Symmons discloses a faucet including a casing surrounding an automatic shut-off valve unit, and a faucet spout. The shut-off valve unit comprises an operating handle, a lower valve body, an upper valve body, a core member, a piston, a stem guide, a valve seat member and a valve closure/piston assembly comprising a piston cylinder and a rubber closure washer. The temperature of water discharged by the faucet is adjustable by rotating the operating handle. However, the mixing valve member is a component of the shutoff valve and is disposed in an in-line configuration with the valve actuator for the shutoff valve. Accordingly, service or replacement of the shutoff valve requires disassembly of the entire valve mechanism for this metering faucet.
Another example, provided in U.S. Pat. No. 4,241,759 to Billeter, is directed to a faucet with a faucet casing mounted to the back of a lavatory deck with the faucet spout overhanging the sink. A control cartridge is removably inserted within the top of the casing and is operated by a knob. The casing has a cold water inlet and a hot water inlet for connection to the cold and hot water supply lines. A mixing valve, responsive to rotation of a cartridge core, is attached to the bottom of the core. Passages allow communication between casing inlets to the mixing valve. In operation, a user can select the desired water temperature by rotating the knob causing the rotation of the mixing valve. The user then depresses the knob to allow water to flow out of the faucet spout. However, this faucet also suffers from various deficiencies.
Accordingly, a need exists for a metering faucet that provides for adjustment in the proportions of hot and cold water in the mix being discharged by the faucet while also being durable, long lasting, and requiring little or no maintenance by the user.